该源码的功能：用C来实现的单向链表，看似不屑一顾，其实不然，风格规范，功能齐全，能使读者学会怎样使用函数指针，能够体会函数指针的神奇的力量。-The source function: C to achieve one-way linked list, it seems dismissive, it is not true, style specifications, functional, enabling readers to learn how to use function pointer